Atrial Fibrillation and Atrial Flutter

Atrial Fibrillation (A Fib)

  • Definition: Atrial fibrillation is one of the most common arrhythmias seen in hospitalized patients, characterized by the atria not beating properly and instead quivering at a very fast and irregular rate.

  • Pathophysiology:

    • The quivering of the atria leads to ineffective blood pumping, resulting in blood pooling.

    • Blood pooling increases the risk of clot formation, which can lead to cerebrovascular accidents (strokes).

  • Identification Criteria:

    • Electrocardiogram (ECG) Findings:

    • Absence of P waves before QRS complexes.

    • Replacement of P waves with irregular fibrillatory waves known as f waves (can be fine or coarse).

    • Atrial rate is typically faster than 400 beats per minute.

    • QRS complexes present, measuring < 0.12 seconds.

    • Ventricular Rate:

    • Can vary from normal to fast (> 100 beats per minute).

    • < 100 beats per minute is termed "controlled A fib."

    • > 100 beats per minute is termed "uncontrolled A fib" which can lead to complications such as heart failure due to ineffective pumping.

    • Unable to measure PR interval or QT interval due to irregular rhythm.

  • Causes:

    • After heart surgery, certain procedures can trigger A fib.

    • Significant heart problems:

    • Valve issues (especially mitral valve), congenital heart diseases, coronary artery disease, post-myocardial infarction, or pericarditis.

    • Lung conditions like chronic obstructive pulmonary disease (COPD).

    • Patients with sleep apnea are particularly at risk and should be screened for this condition.

  • Treatment Options:

    • Determined by patient stability and rate (controlled vs uncontrolled).

    • For Stable Patients:

    • Continue monitoring and notify physician if condition changes.

    • For Unstable Patients:

    • Symptoms include low blood pressure and decreased cardiac output indicating inadequate perfusion.

    • May require synchronized cardioversion, delivering a shock synchronized with the patient's waveforms to restore normal rhythm.

    • Pre-cardioversion assessment: Duration of A fib may necessitate anticoagulation to prevent thromboembolic events.

    • Transesophageal Echocardiogram (TEE) may be performed to check for clots before cardioversion. If no clots are found, electrical cardioversion can proceed.

    • Post-cardioversion anticoagulation may be required for several weeks.

    • Pharmacological Treatment:

    • Cardioversion can also be achieved through medications such as diltiazem (Cardizem), adenosine, and amiodarone.

    • Anticoagulants:

    • Warfarin (Coumadin) is used to reduce clot risk.

    • Rate Control Medications:

    • Beta blockers (e.g. propranolol) and calcium channel blockers (e.g. diltiazem).

    • Further Treatment:

    • If A fib persists, an ablation procedure may be considered to destroy or erode tissue in the heart to prevent future arrhythmias.

Atrial Flutter

  • Definition: Atrial flutter (often referred to as flutter) is a cardiac arrhythmia caused by an abnormal electrical signal leading to rapid atrial contractions.

  • Characteristics:

    • ECG findings:

    • Absence of P waves, replaced by flutter waves with a sawtooth appearance.

    • Atrial rate typically around 300 beats per minute and more regular than A fib.

    • QRS complexes remain present and should measure < 0.12 seconds.

    • The ventricular rate may be either regular or irregular but should not compromise cardiac output.

    • PR intervals, QT intervals, and T waves cannot be measured in this rhythm.

  • Causes:

    • Contributing factors include:

    • Heart valve problems, specifically tricuspid and mitral valve issues.

    • History of myocardial infarction (heart attack) or heart surgery.

    • Hyperthyroidism may also elevate the likelihood of flutter.

  • Treatment Options:

    • Primary goal: Control heart rate and prevent clot formation.

    • Medications:

    • Calcium channel blockers (e.g. diltiazem, Cardizem)

    • Beta blockers (e.g. propranolol)

    • Digoxin for patients with heart failure to enhance heart pumping.

    • Antiarrhythmics (e.g. amiodarone) may be utilized.

    • Anticoagulation:

    • Patients may require anticoagulants, such as warfarin (Coumadin), to mitigate stroke risk due to blood pooling in the atria.

    • Unstable Patients:

    • Similar to A fib, unstable patients may undergo synchronized cardioversion.

    • Ablation:

    • Similar to A fib, ablation may also be indicated for persistent atrial flutter to destroy problematic heart tissue and prevent abnormal signals.